Apparatus for wireless telegraphy.



G. MAROONI. AE AEATUS FOR WIRELESS TELEGRAPHY. APPLIOATION FILED APR. 10, 1908.

935,383, Patented .Sept. 28, 1909.

10 creating UNITED STATES PATENT OFFIQE.

GUGLIELMO LIARCONI, OF ADELPHI, LONDON, ENGLAND, ASSIGNOB T MABCO'NI WIRE- LESS TELEGRAPH COMPANY OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

T 0 all whom it may concern:

Italy, residing at \Vatergate House, Adelphi,

London, England, have invented new and useful .Improvements in Apparatus for Vire-less Telegraphy, of which the following is a specification.

'lhis'invention relates to appliances for trains of electric oscillations, either undamped or very slightly damped, and applying-these to create the corresponding electric Waves required for wireless telegraphy.

The apparatus comprises a metal disk,

which may be called the middle disk, and which is insulated from the earth and can be rotated at a very high speed by means of an electric motor, steam turbine, or engine of any type either directly connected to it or circulation or otherwise.

coupled by; a belt or other gearing. .-'\djacent to the disk are'placed two other insulated "conducting disks, which may be called the polar disks, and which can also be rotated at 25 a high speed by any convenient means, so

that the ad acent parts .of the moving disks are traveling in opposite directions. These polar disks should have their peripheries very close to the surfaces or edges of the 80 middle disk The polar disks, stationary balls, or similar devices which may be used in their stead are placed so. as very nearly to touch thesurfaces of the middle disk. If necessary the balls may be cooled by 'ater disks are connected respectively to the outer ends of two condensers joined in series and hereinafter called the reservoir condenser by means of conductors in which may be in- 40 serted resistances or inductances, and these condensers are also connected through inductive resistances of suitable value to the terminals of 'a source of electric supply which may be either a continuous current 4: dynamo, a secondary battery, an induction coil or transformer, or an alternator of suiiiciently high voltage to discharge across the two small air gaps which separate the middle disk from the polar disks, on either side.

If thegenerator has a sntiiciently low internal resistance the reservoir condenser may be dispensed with.' At some convenient placeon the middle disk a metallic or rubbing contact is provided, and between this contact and themiddle point of the reservoir continuous. or closely adjacent The two polar APPARATUS FOR. WIRELESS TELEGRAPI'IY,

Specification of Letters Patent. Patented Sept. 28, 1909.

Application filed April 10, 1908.

Serial No. 426,185.

condenser or the middle point of the source of electromotive force if this condenser be not used, is inserted an oscillation circuit consisting of a condenser in series with an inductance, which last is connected inductively or conductively to a suitable antenna and to the earth or to a balancing capacity.

Under some circumstances when generators of high elect-romotive force are used aseries of disks maybe employed with their peripheries closely adjacent all rotating at a high speed but so that adjacent portions of neighboring-disks move in opposite directions. In this case the middle disk of the series is connected through a rubbing contact with one end of the oscillating circuit, and the two outside disks with the reservoir condenser or source of electric supply, the other arrangements remaining the same as above described. In any case, to obtain the best results the electric time period of the antenna must be. syntonized with that of the oscillating circuit comprising the condenser and inductance connected between the middle wheel and the center point of the reservoir condenseror the generator.

The drawing is a diag 'ammatic representation of a transmitter in accordance with this invention.

a is the middle disk capable of being rotated at a very high speed by means of a belt pulley or in other convenient way and carried on insulated supports 7) Z), It is found that a peripheral speed of 300 feet. or more per second works well and the disk should of course be so made as to stand such speeds. I

c c are the polar disks connected through resistances or inductances (Z (Z to the outer plates of the reservoir condenser e which plates are also connected through inductive resistances f to a source of electric supply or generator g. In circuit with the middle or neutral point of the reservoir condenser or a neutral point. in the generator circuit and with a brush or contact 7:, on the disk (6 are a condenser and inductance 7r connected either conductively or inductively as shown to an aerial conductor or antenna Z- which is as usual connected to earth or to a capacity. It is prefeablc to have the inductance and resistance of the circuit last. named small as compared with those of eithe arm of the circuitcontaining the reservoir condenser and the polar disks.

The condenser i may in some cases be omitted provided the reservoir condenser is retained.

The polar disks may be placed at such an angle with respect to the middle disk that ing said body at. a. high speed, terminals located adjacent said body and forming spark gaps therewith, a. source of-electric energy connected with said terminals, a condenser connected in parallel with said terminals, and an oscillatory circuit connected with said rotatable body and with the middle or neutral pointof said condenser.

2. In a transmitting apparatus for wireless telegraphy, a source of cmistantelectromotive force, a rotatable disk, means'for ro tating said disk at a high speed, a pairot' metallic terminal disks'connected respectively with the terminals of said source of current and located on opposite sides of the first named disk, a-- condenser connected in parallel with said terminal disks, and an oscillatory circnitconnected with the intermediate disk and with the middle or neutral point of said condenser.

GUGLIEDHO MARCONI.

\Vitnesses Ilnxnr \V. ALLEN, G. F. lVmnnnv. 

